It is known to sample a signal by feeding the signal into the input of a GaAs (or other suitable piezoelectric semiconductor) ACT or into the input of a GaAs/AlGaAs (or other suitable heterostructure) HACT device which injects electrons into a semiconductor layer where they are carried along from an input electrode towards an output electrode by a surface acoustic wave (SAW). For convenience, the term ACT will be taken to mean both ACTs and HACTs. Conventional ACT processing uses tap electrodes positioned between the input and the output electrodes to sample the signal as it passes along the device. It is also known that an ACT/HACT memory structure can be used to impose a uniform blocking potential on the tapping electrodes, so that the attractive force of the potential captures the charge packets and prevents them from being carried by the SAW. When the potential is released, after a variable delay period, the charged packets are carried along by the SAW and are read out at the output electrode at the same rate at which they are entered. Since the speed of SAW input sampling is fast, having a typical SAW frequency range of 50 to 1000 MHz, the readout time between packets may be too fast in general for analog to digital processing of the output signal, or other post signal processing that takes a relatively long time. In addition, conventional ACT/HACT memory device operation results in a uniform delay for all of the stored samples of the input waveform. The art has sought a way to read out stored sampled waveforms at a different and slower rate than the rate at which the input waveform enters a storage device.